Valve-gear for steam-engines.



E. MARSHALL. VALVE GEAE EOE STEAM ENGINES.

I APPLICATION FILED NOV. 22, 1906.

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' PATENTEDAEEES, 1907.

UNTTEE sTATEs PATENT oEErcE.

VALVE-GEAR FOR STEAM-ENGINES.

Specification of Letters Patent.

Patented April 23, 1907.

Application filed November 22,1906. Serial No. 344,614.

To 1f/Z whom t may concern:

Be it known that I, GEORGE MARSHALL, a citizen of the United States of America, residing in Fremont, in the county of Dodge and State of Nebraska, have invented certain new and useful Improvements in Valve- Gear for Steam-Engines, of which the following is a specification.

My invention relates to steam-engines of the class shown, for instance, in my United States Patent No. 612,952, of October 25, 1898. In that patent I have shown mechanism for operating the admission andexhaust valves comprising, among other things, a slotted link operated by an eccentric, a block adjustable by a governor in the link, and a radius-rod connected with the block and also connected with the mechanism for operating the admission-valves of the engines. I have found that the operation of the mechanism may be greatly improved b providing antiriction devices for the block, whereby it may be more easily adjusted by the governor.

In the accompanying drawings I have illustrated my improvements applied to an engine of the general construction shown in my patent above mentioned. j

Figure 1 shows a side elevation of such an engine. Fig. 2 is a erspectve view of the block which works 1n the slotted link and which is connected with the radius-rod. Fig. 3 is a detail view, partly in elevation and partly in section, showing how the block with antifriction devices is arranged in the link, the section being taken on the line 3 of Fig. 4. Fig. 4 shows a section on the line 4 4 of Fig. 3, the link being shown in section and the block in plan.

Inasmuch as my improvements relate entirely to the construction of the block, the other parts of the engine need not be described in detail. The slotted link A is of usual construction, andthe radius-rod B is connected with the valve-operating mechanism of substantially the form shown in my before-mentioned patent. The radius-rod is also connected by a rod O with the governor D. It will be understood that the link is oscillated by the eccentric E and gives a reciprocating motion to the radius-rod B and that the governor D, by means of the connecting-rod C, from time to time changes the vertical position of the block F in the link, and as this block is connected with the radius-rod a differential movement is given to this rod, according to the position of the block in the link.

, In order to cause the block to move easily, I have constructed it in the manner particularly shown in Figs. 2, 3, and 4. The radiusrod B is bifurcated at its end next the link and straddles the link, as shown particularly in Fig. 4. It is pivotally connected with the block by a pin G, which extends through the arms l) of the radius-rod and through the block F. This block is recessed at its upper and lower ends to receive rollers H, having journals h that rotate in bearings formed at opposite sides of the recesses. A pair of rollers is employed at each end of the block, and each pair is so mounted that the two rollers are in contact with each other and are arranged to make contact with the front and rear walls of the slot in the link, so that as the block is raised and lowered in the link the rollers are made to revolve together in the manner indicated by the arrows in Fig. 3. The body of the block is of substantially the same Width as the link but on each side at its upper and lower ends it is formed with projections F, which extend out beyond the sides of the link, and between these projections the arms b of the radius-rod are arranged. The bearings for the journals 7L are formed in these enlargements, and a long bearing is thus formed for each journal. In order to lubricate the journals, I form lubricating-openings I in the enlargements over the journals, and in order to lubricate the pin G, I form a recess K to catch the oil from the to rollers and a conduit L, which leads the oi to an annular recess M, formed in the block around the pin G. In this way all the journals are kept well lubricated and an easy adjustment may be effected. I may, as illustrated, form enlargements or iront and rear rejections N midway between the upper and ower ends of the lblock to bear against the front and rear Walls of the link to take strain from the journals of the rollers. These projections have only a small surface in contact with the Walls of the link and will not produce much friction. When the block is being raised and lowered, the bearing-surfaces Will be mostly against the rollers; but as the IOO link oscillates to reciprocate the radius-rod nals in said bearings, a biurcated radius-rod, most of the strain may be taken by the proa pin pivotally connecting the rod With the jections referred to. block and means for conveying oil through I claim as my inventionthe block to the pin. 5 The combination of a slotted link, a block In testimony whereof I have hereunto sub- 1 5 mounted therein having recesses at its upper i scribed my name. and lower ends and enlargements on Oppo- GEORGE MARSHALL. site sides of the recesses provided Iwith bear- Witnesses: p ings and lubricating-apertures, rollers ar- W. J. COURTRIGHT, 1o ranged in said recesses and having their jour- VANARDA KURTZ. 

